In handling a hypodermic needle, there is always a chance that the user, or persons in the proximity of the needle, may be exposed to accidental pricking thereby. And in view of the current crop of infectious diseases, particularly the as yet incurable Acquired Immune Deficiency Syndrome (AIDS), an urgent need exists to provide a safety device for preventing accidental pricking by a needle, especially one that has been used and is therefore contaminated.
There are in the prior art a number of safety devices for guarding a needle, or more precisely its cannula, so that its sharp end will not be exposed. For example, Sponsel U.S. Pat. No. 1,779,451 discloses a syringe that has a needle guide pivotable at a point about the syringe casing for guarding the needle. Scislowicz U.S. Pat. No. 3,323,523 discloses a sheath formed of two portions that can pivot about respective hinges to cover a cannula. Moreover, the sheath may be locked by having a sleeve slid thereover. Hall U.S. Pat. No. 3,658,061 discloses a catheter needle guard unit that may be pivoted to snap over the needle. The sheath, once snapped, may be unsnapped since it is not locked onto the needle. Smith, Jr. U.S. Pat. No. 4,643,722 discloses a hypodermic needle assembly that has a closure having an elongated slot which enables the closure to be either removed from or inserted toward the hypodermic needle. The Smith device requires two-handed operation. Furthermore, no locking means is disclosed. Nelson et al. U.S. Pat. No. 4,659,330, on the other hand, discloses a needle protective cap which is slidable, by means of a clip, along the body of the syringe. The needle cover, however, may be completely removed from the needle.
Additional slidable needle protectors are disclosed in Spencer U.S. Pat. Nos. 4,702,738 and 4,723,943 wherein a protective sheath is shown to be slidable along a syringe body. Yet other needle covers that are slidable along a syringe body are disclosed in Choksi U.S. Pat. No. 4,737,144 and Schneider U.S. Pat. No. 4,743,233. Some other example devices having protective sheaths for needles include Laico et al. U.S. Pat. No. 4,804,372; Poncy U.S. Pat. No. 4,816,022; Schramm U.S. Pat. No. 4,826,491; Poncy U.S. Pat. No. 4,842,587; Carrell et al. U.S. Pat. No. 4,846,796; Romano U.S. Pat. No. 4,850,968; Bayless U.S. Pat. No. 4,850,977; Zerbst et al. U.S. Pat. No. 4,850,994; Cree U.S. Pat. No. 4,850,996; Jordan et al. U.S. Pat. No. 4,858,607; Bayless U.S. Pat. No. 4,863,434 and Haber U.S. Pat. No. 4,892,107. As is readily apparent, all of these devices having covers that are slidable along the length of the syringe body require two-handed operation.
Another type of prior art needle protective device involves the pivoting of a needle sheath to cover the cannula of the needle assembly. Some prior art examples of this type of device include Norelli U.S. Pat. No. 4,820,277 wherein a pair of jaws is disclosed as pivotable and lockable over a needle. As is readily apparent, however, the Norelli cover also requires two-handed operation. Glazier U.S. Pat. No. 4,883,469 discloses a guard assembly that is coupled to a sheath by a fastener and is rotatable about a hinge to snap onto the needle. The sheath, along with the pivotable guard, has to be preassembled with the needle for a specific type of syringe. Schoenberg U.S. Pat. No. 4,888,001 discloses a longitudinal shank having two flat wings which are pivotable to enclose the sharp distal end of the needle. None of these prior art devices appears to disclose the permanent retention of the needle by the protective sheath once the protective sheath has been pivoted to enclose the needle.
There are a couple of prior art safety devices that do teach the permanent retention of a needle within the housing once it has been enclosed thereby. Landis U.S. Pat. No. 4,664,259 is one such which discloses a needle assembly that includes a pivotable housing having therein a hook to retain the needle within the housing after the housing has been pivoted to enclose the needle. The Landis device, however, comes in a unitary package, inasmuch as the needle is integrated into the base, which in turn has connected thereto the pivotable housing. Unger U.S. Pat. No. 4,872,552 also discloses a pivotable housing integrated into a needle. In one of the embodiments, the Unger housing is threaded to a specific type of needle housing hub. To lock the housing permanently to the needle, a plug has to be pushed from the top of the housing longitudinally (along the length of needle) into the housing until the tip of the needle rests within the plug. To operate the Unger device, a user has to first pivot the housing into alignment with the needle, hold the housing to maintain alignment of the needle therewith and then push the plug flush with the end of the housing in order to lock the needle within the housing. Needless to say, there is always a chance that if the user is not careful in maintaining the needle within the housing before pushing the plug flush to the end of the housing, the tip of the needle may remain exposed; and, therefore, the user may actually be moving his hand/finger directly into contact with the needle.
Inasmuch as there is available in the market a number of different types of needles and syringes, there is a need to have a universal safety device that is adaptable to be used with the different types of needles and syringes. And it is imperative that such safety device be amendable to single-handed operation, as for example during emergency room situations where a user may have only one hand free. Furthermore, to provide extra protection to ensure that the tip of the needle, especially after use, is not exposed, some means must be used to seal the same.
Finally, it has been found that oftentimes there is a large unused and therefore wasteful volume of space at the junction where the syringe and needle are joined which has to be filled with blood to be drawn from or fluid to be injected into a patient.